An assessment of the time-dependence structure of streams in New Jersey, USA

The lag-one serial correlation coefficient is one of the important hydrological metric used as a quantitative measure of carry-over capacity of water stored within a catchment. In this study, the annual lag-one serial correlation coefficient has been computed for 27 unregulated streams spread across the two main climatic regions of New Jersey, USA. The computed mean annual lag-one serial correlation coefficient was found to be 0.17, which is typical of the national value. It appears that streams that drain northern catchments have higher carry-over capacity in comparison to their southern counterparts. Further, the Goud-Dincer Gamma method of reservoir storage capacity was used to compare the average reservoir storage needed to meet the over-year storage requirement for a hypothetical reservoir located within the two main climatic regions. The results revealed that on average, a reservoir needed to meet over-year storage requirements in climate region 1 (northern New Jersey) needs to be a little more than one half times as large as those in climate region 2 (southern New Jersey) for the same level of regulation. Though groundwater recharge to streams in the southern catchments are generally higher than their northern counterparts, it appears relatively less ground water (release from storage) in any given year in the south is carried from the previous year(s).